Failure to update

I recently purchased an unlocked sprint galaxy s4 from ebay/china running 4.4.2

A software update downloaded but failed to install with this message:

"/system/media/BST_bootsamsung.qmg" has unexpected contents.
E: Error in /cache/update.zip (status 7) Installation aborted.

Can anyone help?

Nexus 6 SIM Network unlock Failure. Now wont recognize any carrier.

I tried to carrier unlock my nexus 6 from AT&T. I purchased this device used. No warranty. Didn't think it was going to be a big deal. Paid the 10 - 15 bucks for the code. Tried it. Had issues. Responded back to the Code Unlocking company, got a new one. Tried it. Doesn't work. Now the phone wont connect to any service, not even AT&T. Nor will it prompt for the code.

I read later that I should not have done this with a custom rom, Cyanogenmod, and that may have been my issue. I feel I know that the system does recognize the sim, but doesn't know how to process the data because of a software issue. I would be okay if I carrier locked it, but it doesn't even work with AT&T. I have tried all releases for the Nexus 6 that were compatible.

Things I have tried:
Manual ADB for many versions
Nexus Root Toolkit many versions


This is my last ditch effort before I sell it for parts. Any help is appreciated. I will take any risks at this point.

Sensors' general failure

Hi, I have a 925I and suddenly all sensors have stopped working. I mean all of them, accelerometer, gyroscope, light, magnetic, barometer, etc. They all fail the *#0*# selftests. Screen does not rotate, and camera doesn't take landscape pictures.
I'm running 5.1.1 IDVU2DOI2.
Any ideas?

FAILED (data transfer failure (Unknown error)) when trying to flash anything to phone

I have S-ON and a non-HK phone with an OS of 2.16.651 I believe. @Sloth tried to help me but to no success, so I'll try to see if anybody else can help me figure out the issue.
Basically, everything works up until I actually start to flash the phone. It gives me this error:
FAILED (data transfer failure (Unknown error))
There's a bit more to it, but that's mostly unrelated stuff (the command and blahblahblah).

I've tried 2 different computers and different ports on all of them. I don't have any other USB cables for my phone available, but this one works with my PS4 controllers finely so I'm guessing it should work fine.

If someone could help me and anyone else with my luck in the future, please answer. I don't want to have to resort to a store as I have no money and the store is quite far. Thanks!

EDIT: Something else to mention, there is no firmware on this device and only has an accessible bootloader and recovery. I currently have the bootlocker relocked. I had ViperOneM8, although uninstalled after realizing I had no access to WiFi (I ignored the disclaimer :c). I don't have a SIM card as this phone was given and I didn't buy it myself from any carrier, I have no service.